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DOE OSTI2022

A scintillator attenuation spectrometer for intense gamma-rays

A new type of compact high-resolution high-sensitivity gamma-ray spectrometer for short-pulse intense gamma-rays (250 keV to 50 MeV) has been developed by combining the principles of scintillators and attenuation spectrometers. The first prototype of this scintillator attenuation spectrometer (SAS) was tested successfully in Trident laser experiments at LANL. Later versions have been used extensively in the Texas Petawatt laser experiments in Austin, TX, and more recently in OMEGA-EP laser experiments at LLE, Rochester, NY. The SAS is particularly useful for high-repetition-rate laser applications. Furthermore, we give a concise description of the design principles, capabilities, and sample preliminary results of the SAS.

47 OTHER INSTRUMENTATION↗

DOE OSTI2021

Enhancements in laser-generated hot-electron production via focusing cone targets at short pulse and high contrast

We report on the increase in the accelerated electron number and energy using compound parabolic concentrator (CPC) targets from a short-pulse (~150 fs), high-intensity (>10 18 W/cm 2 ), and high-contrast (~10 8 ) laser-solid interaction. We report on experimental measurements using CPC targets where the hot-electron temperature is enhanced up to ~ 9 times when compared to planar targets. The temperature measured from the CPC target is (T e ) = 4.4 ± 1.3 MeV. Using hydrodynamic and particle in cell simulations, we identify the primary source of this temperature enhancement is the intensity increase caused by the CPC geometry that focuses the laser, reducing the focal spot and therefore increasing the intensity of the laser-solid interaction, which is also consistent with analytic expectations for the geometrical focusing.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗